Abstract

Photonic integration of optical packet switching modules is crucial to compete with
existing electronic switching fabrics in large data center networks. The approach of coding the
forwarding packet information in an in-band label enables a spectral-efficient and scalable way of
building low-latency large port count modular optical packet switching architecture. We
demonstrate the error-free operation of the four in-band label extraction from ${160 Gb/s}$ optical data packets based on photonic integrated silicon-on-insulator ring
resonators. Four low-loss cascaded ring resonators using the quasi-TM mode are used as narrowband
filters to ensure the detection of four optical labels as well as the error-free forwarding of the
payload at limited power penalty. Due to the low-loss and less-confined optical quasi-TM mode the
resonators can be very narrowband and have low insertion loss. The effect of the bandwidth of the
four ring resonators on the quality of the payload is investigated. We show that using four rings
with 3dB bandwidth of ${21 pm}$ and only an insertion loss of ${3 dB}$, the distortion on the payload is limited (${<}1.5\,{\rm dB}$ power penalty), even when the resonances are placed very close to the packet’s
central wavelength. We also investigate the optical power requirements for error-free detection of
the label as function of their spectral position relative to the center of the payload. The
successful in-band positioning of the labels makes this component very scalable in amount of
labels.